3 Answers
3

Metals Metal ores your Sims collect in the Sims 3 can be smelted for $40. Because of this cost, and the fact that ingots seem to return
at 175% of original value, you shouldn't smelt anything under $54.
However, once you have completed the Metal Collector challenge
(finding all five types of metal) you will sometimes get extra ingots
in the mail. This means you could smelt items in the $40 range because
you'll often get extra ingots back. Ingots can be stacked. If you want
to make an impressive display, make a table with stacks of ingots!

here are precious metals, well, they are found in their ore form, and you
then need to send it off to a smelter, who will smelt it down, for a fixed
fee of §40, regardless of the ore. This will turn the relatively valueless
ore into something that is a bit more valuable, an ingot that will get a 75%
increase in value after it is smelted.

Again, rarity means that you will need to constantly look hard to find the
ore that you want, the plutonium ore, which is somehow, safe to pick up.

Like gems, the metals are determined by weight, the heavier it is, the more
it is valued. Mercury and Platinum are found in China, Copper and Mummitomium
are found in Egypt, Titanium and Iridium are found in France, whilst
Supernovium and Compendium are special, again, a seperate section for them.

They can be placed on a lot, where they help attribute to the enivronment score of the room (though anything else with a non-negative cost does, so they're not exclusive that way), or sold for simoleans if you'd prefer the cash.

Metals in the Sims 3 can be smelted (transformed from ores to ingots), which will increase their value, however the smelting process costs a bit so smelting anything worth less than 54 Simoleaons isn't a good investment.

If you have the World Adventures expansion, you can also transfigure metal ingots into larger ingots or other metals by placing several ingots on the Carter's Display Case XL Edition display case. This will usually result in higher value metals. You can read about transfiguration of metals (and other items) in this guide.